A process for the production of fine wires

Abstract

The application discloses a micro-wire production and preparation process and belongs to the technical field of micro-wire processing, which is used for solving the technical problem that the flexibility, insulation performance, high-temperature resistance and bonding strength of the micro-wire in the prior art need to be further improved, and specifically comprises the following steps: taking a copper block as raw material, performing smelting, rolling and stretching treatment to prepare a fine wire conductor with a diameter of 0.13-0.15 mm, depositing a polydopamine layer formed by mixing hydrochloric acid dopamine and a buffer on the surface of the fine wire conductor, namely, increasing the temperature of a reaction system to 50-60 DEG C, performing ultrasonic dispersion, adding the fine wire conductor into the reaction system, and performing ultrasonic deposition for 3-5 h, and then performing post-treatment to obtain a pretreated conductor; the polydopamine is used for coating and modifying the fine wire conductor, and then the polydopamine is coated with a polysiloxane reinforcing agent reinforced polyimide reinforcing body, so that the flexibility and high-temperature resistance of the micro-wire are effectively improved, and the bonding strength and minimum breakdown voltage of the micro-wire are also improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-wire processing, and particularly relates to a production and preparation process of micro-wire. BACKGROUND

[0002] With the development of the fields of aerospace, microelectronic packaging, precision instruments and flexible electronic devices, there is an increasing demand for micro-wire materials that have high flexibility, excellent insulation performance and excellent heat resistance.

[0003] In the prior art, polyimide is often used as an insulating coating material for micro-wire. The polyimide insulating layer is prone to cracking when the micro-wire is bent or dynamically deformed due to the large rigidity of the molecular chain, which limits its application in high-frequency vibration or complex curved surface wiring scenarios. The initial decomposition temperature of conventional polyimide is usually lower than 500 DEG C, and thermal degradation easily occurs in a high-temperature environment. Moreover, the conductor and the insulating layer are combined through physical adsorption, and peeling easily occurs under the action of thermal cycling or mechanical stress, resulting in insulation failure. Therefore, the polyimide cannot meet the requirements of long-term heat resistance and high adhesion strength. In addition, the breakdown voltage of traditional polyimide is limited by the molecular structure, and it is difficult to meet the demand for high insulation strength in high-voltage pulse application scenarios (such as electric vehicle motor windings).

[0004] Therefore, the present application provides a solution. SUMMARY

[0005] The present application aims to provide a production and preparation process of micro-wire, which can solve the technical problems that the flexibility, insulation performance, high-temperature resistance and adhesion strength of the micro-wire in the prior art need to be further improved.

[0006] The present application can be achieved by the following technical solution: a production and preparation process of micro-wire, comprising the following steps:

[0007] S1, using a copper block as a raw material, a fine wire conductor with a diameter of 0.13-0.15 mm is prepared, a layer of polydopamine is deposited on the surface of the fine wire conductor, and a pretreated conductor is prepared;

[0008] S2, mixing and stirring aniline modified fluorine-containing polysiloxane, diethyl(chloromethyl) phosphine oxide, toluene and an alkali catalyst, increasing the temperature of the reaction system to 74-78 DEG C, and keeping the reaction for 6-8 h, and then treating to obtain a polysiloxane reinforcing agent;

[0009] The synthesis reaction equation of the polysiloxane reinforcing agent is as follows:

[0010]

[0011] The synthesis reaction mechanism of the polysiloxane reinforcing agent is as follows:

[0012] During the reaction, the base catalyst catalyzes the nucleophilic substitution reaction between the olefin double bond on the aniline modified fluorine-containing polysiloxane molecule and the halogen on the diethyl(chloromethyl)phosphine oxide molecule, and modifies the diethyl phosphine oxide on the aniline modified fluorine-containing polysiloxane molecule. In the reaction, the diethyl(chloromethyl)phosphine oxide is used in excess, and impurities are removed by vacuum distillation to prepare the polysiloxane reinforcing agent.

[0013] S3, the polysiloxane reinforcing agent, 4,4'-diamino diphenyl ether, catalyst and DMSO are mixed and stirred, the reaction system temperature is raised to 130-150℃, and the system is stirred until it is dissolved. A solution of pyromellitic dianhydride is added to the reaction system, and the reaction is kept for 4-6h. After treatment, the polyimide reinforcing agent is obtained.

[0014] The synthesis reaction mechanism of the polyimide reinforcing agent is:

[0015] During the reaction, the catalyst catalyzes the ring opening of the anhydride on the pyromellitic dianhydride molecule, and reacts with the amino group on the polysiloxane reinforcing agent and 4,4'-diamino diphenyl ether molecule to form a polyamide acid prepolymer. The modified polyamine on the polysiloxane reinforcing agent effectively improves the intermolecular crosslinking degree of the polyamide acid prepolymer, and the polyimide reinforcing agent is prepared.

[0016] S4, the polyimide reinforcing agent is coated on the outside of the pretreated conductor, and a polyimide coating layer with a thickness of 10-13μm is coated on the outside of the pretreated conductor. After high-temperature thermal imidization treatment, the fine wire is obtained.

[0017] Further, the pretreated conductor is processed by the following steps:

[0018] A1, after melting the copper block, the copper block is subjected to rolling and stretching treatment to obtain a fine wire conductor with a diameter of 0.13-0.15mm.

[0019] A2, the hydrochloric acid dopamine and the buffer are mixed, the reaction system temperature is raised to 50-60℃, and the fine wire conductor is added to the reaction system. After ultrasonic deposition for 3-5h, the pretreated conductor is obtained after treatment.

[0020] The synthesis reaction mechanism of the pretreated conductor is:

[0021] During the reaction, under weak alkaline conditions, dopamine molecules are first oxidized to dopaminequinone, and then dopaminequinone reacts with unoxidized dopamine molecules to form dimers, trimers and other oligomers. Finally, the dopamine is polymerized into a high molecular weight polydopamine. After the fine wire conductor is added to the reaction bottle, the polydopamine is deposited on the surface of the conductor by physical adsorption or chemical bonding. The polydopamine layer has good adhesion and can be firmly attached to the surface of the conductor to form a uniform coating, and the pretreated conductor is prepared.

[0022] Further, in step A1, the purity of the copper block is 99.98%, in step A2, the ratio of the amount of dopamine hydrochloride, buffer and filament conductor is 1g:500mL:5g, the buffer is 0.3mol / L trimethylamine hydrochloride aqueous solution with pH=8.5, and the post-treatment comprises: after the reaction is completed, the filament conductor is taken out of the solution, dried after washing with purified water, and a pretreated conductor is obtained.

[0023] Further, in step S2, the ratio of the amount of aniline modified fluorine-containing polysiloxane, diethyl(chloromethyl)phosphine oxide, toluene and base catalyst is 5g:2g:50mL:1g, the base catalyst is triethylamine, and the post-treatment comprises: after the reaction is completed, the temperature of the reaction system is increased to 85℃, and low-boiling substances are removed by reduced pressure evaporation, and a polysiloxane reinforcing agent is obtained.

[0024] Further, in step S3, the ratio of the amount of polysiloxane reinforcing agent, 4,4'-diamino diphenyl ether, catalyst and DMSO is 2g:3g:0.5g:10mL, the catalyst is 4-dimethylamino pyridine, the molar ratio of pyromellitic dianhydride to amino in the reaction system is 2:1, the pyromellitic dianhydride solution is composed of pyromellitic dianhydride and DMSO at a ratio of 1g:1mL, and the post-treatment comprises: after the reaction is completed, the reaction system is cooled to 100℃, and a polyimide reinforcing body is obtained.

[0025] Further, the preparation method of the aniline modified fluorine-containing polysiloxane comprises: mixing and stirring D4, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3,3,3-trifluoropropyl)cyclotetrasiloxane, aniline modified diethoxysilane and a catalyst, increasing the temperature of the reaction system to 90-100℃, and keeping the reaction for 2-3h, adding diallyl tetramethyl disiloxane to the reaction system, keeping the reaction for 3-5h, and post-treating to obtain the aniline modified fluorine-containing polysiloxane.

[0026] The synthesis reaction equation of the aniline modified fluorine-containing polysiloxane is:

[0027]

[0028] In the formula:

[0029] The synthesis reaction mechanism of the aniline modified fluorine-containing polysiloxane is:

[0030] During the reaction, the catalyst catalyzes the ring-opening of D4, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3,3,3-trifluoropropyl)cyclotetrasiloxane molecules to form long siloxane branches with silanol modification, at the same time, the siloxane bond of aniline-modified diethoxysilane molecules is hydrolyzed to form silanol, then dehydration condensation occurs between silanols to form long siloxane segments with aniline and trifluoropropyl modification, and diallyl tetramethyldisiloxane as an end-capping group forms an olefin end-capping modification on the long polysiloxane chain to prepare aniline-modified fluorosilicone.

[0031] Further, the molar ratio of D4, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3,3,3-trifluoropropyl)cyclotetrasiloxane, aniline-modified diethoxysilane and diallyl tetramethyldisiloxane is 3:1:1:1, the dosage ratio of D4 and catalyst is 5g:1mL, the catalyst is 40-60wt% sulfuric acid, and the post-treatment includes: after the reaction is completed, the temperature of the reaction system is reduced to room temperature, 0.1mol / L aqueous sodium carbonate solution is added to the reaction system, the pH of the system is adjusted to 7, it is left to stand and separate, the upper solution is washed with saturated sodium chloride solution twice and then washed once with purified water, and the upper solution is transferred to a rotary evaporator with a water bath temperature of 75-85℃, and low-boiling substances are removed under reduced pressure to obtain aniline-modified fluorosilicone.

[0032] Further, the preparation method of the aniline-modified diethoxysilane is: o-phenylenediamine and tetrahydrofuran are stirred and mixed under inert gas protection, the temperature of the reaction system is increased to 40-50℃, 3-isocyanate propyl methyl diethoxysilane solution is added dropwise to the reaction system, and the reaction is kept for 60-80min, and then post-treated to obtain aniline-modified diethoxysilane.

[0033] The synthesis reaction equation of aniline-modified diethoxysilane is:

[0034]

[0035] The synthesis reaction mechanism of aniline-modified diethoxysilane is:

[0036] During the reaction, the isocyanate group on the 3-isocyanate propyl methyl diethoxysilane molecule reacts with the amino group on the o-phenylenediamine molecule to form aniline modification on the diethoxysilane molecule by controlling the dosage ratio of the reaction and using the high steric hindrance of the o-phenylenediamine molecule to prepare aniline-modified diethoxysilane;

[0037] The mass spectrometry analysis data of the aniline-modified diethoxysilane is m / z: 325.18217 (100.0%), 326.18552 (16.2%), 326.18174 (5.1%), 327.17901 (3.3%), 327.18888 (1.2%), 326.17920 (1.1%).

[0038] Further, the molar ratio of the o-phenylenediamine and 3-isocyanate propyl methyl diethoxysilane is 1:1, the ratio of the o-phenylenediamine and tetrahydrofuran is 1g:4mL, the 3-isocyanate propyl methyl diethoxysilane solution is composed of 3-isocyanate propyl methyl diethoxysilane and tetrahydrofuran at a ratio of 1g:1mL, and the post-treatment comprises: after the reaction is completed, the temperature of the reaction system is increased to 65℃, and low-boiling substances are removed by evaporation under reduced pressure to obtain the aniline-modified diethoxysilane.

[0039] Further, in step S4, the preparation method of the fine wire is:

[0040] B1, the pretreated conductor is immersed in the polyimide reinforcing body to coat the polyimide coating layer with a thickness of 10-13um outside the pretreated conductor, and a fine wire crude product is prepared;

[0041] B2, the fine wire crude product is subjected to thermal imidization treatment at a temperature of 260-280℃ for 20-30min to obtain the fine wire.

[0042] The present application has the following advantages:

[0043] 1, the present application is through polydopamine to the copper core fine wire conductor coating modification, reduce the pinhole defect of fine wire conductor, avoid partial discharge, guarantee the breakdown voltage stability, and, hydrochloric acid dopamine forms strong adhesion polydopamine layer on the copper surface, through hydrogen bond and pi-pi stacking effect enhances the interface combination of polyimide, so that the polyimide reinforcing body can be uniformly attached to the fine wire conductor, and through thermal imidization reaction, imide ring is formed, polyimide is obtained, the conjugated structure and high crystallinity of imide ring endow it with excellent dielectric strength and high temperature resistance, improve the minimum breakdown voltage and high temperature decomposition temperature of the fine wire.

[0044] 2、The application also carries out amidation reaction on the polysiloxane reinforcing agent, 4, 4'-diamino diphenyl ether and pyromellitic dianhydride to prepare a polyimide reinforcing body, the polysiloxane chain of the polysiloxane reinforcing agent molecular chain has good flexibility, gives the molecular chain high flexibility and rotation freedom, after the introduction of aniline modified fluorine-containing polysiloxane, the flexible chain segment is dispersed in the rigid aromatic ring structure of the polyimide main chain, the flexibility of the material is significantly improved, the trifluoropropyl modified on the polysiloxane has low polarizability and strong hydrophobicity of fluorine atoms, which can reduce intermolecular forces, further reduce internal friction of the material, enhance the bending resistance, and the strong electronegativity of the fluorine atom makes the C-F bond have low polarizability and high chemical inertness, inhibits the oxidation reaction and free radical chain reaction, delays thermal decomposition, and the fluorine atom can also stabilize the Si-O-Si main chain through the steric hindrance effect, reduce the tendency of polysiloxane chain to break down at high temperature, and make up for the defects of the high temperature stability of polysilane.

[0045] 3、The application also modifies diethyl phosphine oxide which can decompose to generate phosphoric acid at high temperature on the aniline modified fluorine-containing polysiloxane molecule, promotes the formation of a carbon layer through a condensed phase flame retardant mechanism, thereby insulating heat and oxygen, delaying the thermal decomposition process of the material, and the synergistic effect of phosphorus and fluorine can further enhance the density and stability of the carbon layer, thereby improving the thermal decomposition temperature, the aniline on the polysiloxane reinforcing agent serves as an active reaction site for amidation reaction, increasing the degree of intermolecular crosslinking of the reaction, limiting the movement of polymer chain segments, reducing the chain scission tendency in the initial stage of thermal decomposition, thereby improving thermal stability and breakdown voltage, and the strong electronegativity of the trifluoropropyl group can also inhibit charge migration, improve dielectric strength. DETAILED DESCRIPTION

[0046] The technical solutions of the application will be described below in connection with the embodiments, obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0047] In the application, D4 is octamethylcyclotetrasiloxane, and the CAS number is 556-67-2.

[0048] In the application, DMSO is dimethyl sulfoxide, and the CAS number is 67-68-5.

[0049] Example 1

[0050] The embodiment provides a preparation method of a polyimide reinforcing body, comprising the following steps:

[0051] Step one, preparation of aniline modified diethoxysilane

[0052] Weighing: 3-isocyanate propyl methyl diethoxysilane 21.7 g and tetrahydrofuran 21.7 mL are uniformly mixed to obtain a 3-isocyanate propyl methyl diethoxysilane solution, which is used as prepared;

[0053] Weighing: o-phenylenediamine 10.8 g and tetrahydrofuran 43.2 mL are stirred in an argon-protected reaction bottle, the temperature of the reaction bottle is increased to 40°C, and the above-prepared 3-isocyanate propyl methyl diethoxysilane solution is added dropwise to the reaction bottle. After the dropwise addition is completed, the reaction is incubated for 60 min, the temperature of the reaction bottle is increased to 65°C, and low-boiling substances are removed by evaporation under reduced pressure to obtain aniline-modified diethoxysilane.

[0054] Step two, preparation of aniline-modified fluorosilicone

[0055] Weighing: D4 89.0 g, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3,3,3-trifluoropropyl)cyclotetrasiloxane 62.5 g, aniline-modified diethoxysilane 32.5 g, and 40 wt% sulfuric acid 17.8 mL are stirred in a reaction bottle, the temperature of the reaction bottle is increased to 90°C, and the reaction is incubated for 2 h. Diallyl tetramethyl disiloxane 21.4 g is added to the reaction bottle, and the reaction is incubated for 3 h. The temperature of the reaction bottle is reduced to room temperature, 0.1 mol / L aqueous sodium carbonate solution is added to the reaction bottle to adjust the pH of the system to 7, and the system is allowed to stand and separate. The upper solution is washed twice with saturated sodium chloride solution and then once with purified water. The upper solution is transferred to a rotary evaporator with a water bath temperature of 75°C, and low-boiling substances are removed by evaporation under reduced pressure to obtain aniline-modified fluorosilicone.

[0056] Step three, preparation of polysiloxane reinforcing agent

[0057] Weighing: aniline-modified fluorosilicone 200 g, diethyl(chloromethyl)phosphine oxide 80 g, toluene 2000 mL, and base catalyst triethylamine 40 g are stirred in a reaction bottle, the temperature of the reaction bottle is increased to 74°C, and the reaction is incubated for 6 h. The temperature of the reaction bottle is increased to 85°C, and low-boiling substances are removed by evaporation under reduced pressure to obtain a polysiloxane reinforcing agent.

[0058] Step four, preparation of polyimide reinforcing body

[0059] Take: polysiloxane reinforcing agent 100 g, 4,4'-diamino diphenyl ether 150 g, catalyst 4-dimethylaminopyridine 25 g and DMSO 500 mL into the reaction bottle stirring, the reaction bottle temperature rises to 130℃, stirring to system dissolution, according to the reaction bottle in the reactant amino molar amount of 1 / 2 calculation of pyromellitic dianhydride addition amount, and pyromellitic dianhydride and DMSO mixed evenly 1 g: 1 mL, get pyromellitic dianhydride solution, pyromellitic dianhydride solution drop into the reaction bottle, drop to completion, incubation reaction 4 h, post-processing, the reaction bottle cooling to 100℃, get polyimide reinforcing body.

[0060] Example 2

[0061] The present embodiment provides a kind of preparation method of polyimide reinforcing body, comprising the following steps:

[0062] Step one, preparation of aniline modified diethoxysilane

[0063] Take: 3-isocyanate propyl methyl diethoxysilane 21.7 g and tetrahydrofuran 21.7 mL are mixed evenly, to obtain 3-isocyanate propyl methyl diethoxysilane solution, standby;

[0064] Take: o-phenylenediamine 10.8 g, tetrahydrofuran 43.2 mL is added into the reaction bottle under argon protection stirring, the reaction bottle temperature rises to 45℃, the above-mentioned mixed 3-isocyanate propyl methyl diethoxysilane solution is added dropwise into the reaction bottle, drop to completion, incubation reaction 70 min, the reaction bottle temperature rises to 65℃, low boiling point is removed by evaporation under reduced pressure, to obtain aniline modified diethoxysilane.

[0065] Step two, preparation of aniline modified fluorine-containing polysiloxane

[0066] Take: D4 89.0 g, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis (3,3,3-trifluoropropyl) cyclotetrasiloxane 62.5 g, aniline modified diethoxysilane 32.5 g and 50 wt% sulfuric acid 17.8 mL are added into the reaction bottle stirring, the reaction bottle temperature rises to 95℃, incubation reaction 2.5 h, diallyl tetramethyl disiloxane 21.4 g is added into the reaction bottle, incubation reaction 4 h, the reaction bottle temperature reduces to room temperature, 0.1 mol / L sodium carbonate aqueous solution is added into the reaction bottle, adjust the system pH=7, stand and separate, the upper solution is washed with saturated sodium chloride solution twice and then washed with purified water once, the upper solution is transferred to the rotary evaporator with water bath temperature of 80℃, low boiling point is removed by evaporation under reduced pressure, to obtain aniline modified fluorine-containing polysiloxane.

[0067] Step three, preparation of polysiloxane reinforcing agent

[0068] Take: aniline modified fluorine-containing polysiloxane 200 g, diethyl (chloromethyl) phosphine oxide 80 g, toluene 2000 mL, base catalyst triethylamine 40 g into the reaction bottle stirring, the reaction bottle temperature rises to 76 ℃, heat preservation reaction 7 h, the reaction bottle temperature rises to 85 ℃, the low boiling point is removed by evaporation under reduced pressure, polysiloxane reinforcing agent is obtained.

[0069] Step four, preparation of polyimide reinforcing body

[0070] Take: polysiloxane reinforcing agent 100 g, 4,4'-diamino diphenyl ether 150 g, catalyst 4-dimethylaminopyridine 25 g and DMSO 500 mL into the reaction bottle stirring, the reaction bottle temperature rises to 140 ℃, stirring until the system is dissolved, the addition amount of pyromellitic dianhydride is calculated according to 1 / 2 of the amino molar amount of the reactants in the reaction bottle, and pyromellitic dianhydride and DMSO are mixed uniformly at 1 g: 1 mL, to obtain a pyromellitic dianhydride solution, drop the pyromellitic dianhydride solution into the reaction bottle, after the drop is completed, heat preservation reaction 5 h, post-processing, the reaction bottle is cooled to 100 ℃, and the polyimide reinforcing body is obtained.

[0071] Example 3

[0072] The present embodiment provides a method for preparing a polyimide reinforcing body, comprising the following steps:

[0073] Step one, preparation of aniline modified diethoxysilane

[0074] Take: 3-isocyanate propyl methyl diethoxysilane 21.7 g and tetrahydrofuran 21.7 mL, mix uniformly to obtain 3-isocyanate propyl methyl diethoxysilane solution, ready for use;

[0075] Take: o-phenylenediamine 10.8 g, tetrahydrofuran 43.2 mL into the argon-protected reaction bottle stirring, the reaction bottle temperature rises to 50 ℃, the above-mentioned mixed 3-isocyanate propyl methyl diethoxysilane solution is added dropwise into the reaction bottle, after the drop is completed, heat preservation reaction 80 min, the reaction bottle temperature rises to 65 ℃, the low boiling point is removed by evaporation under reduced pressure, and the aniline modified diethoxysilane is obtained.

[0076] Step two, preparation of aniline modified fluorine-containing polysiloxane

[0077] Take: D4 89.0g, 2,4,6,8-tetramethyl-2,4,6,8-tetra(3,3,3-trifluoropropyl) cyclotetrasiloxane 62.5g, aniline modified diethoxysilane 32.5g and 60wt% sulfuric acid 17.8mL into the reaction bottle stirring, the reaction bottle temperature rises to 100℃, keep the reaction for 3h, add diallyl tetramethyl disiloxane 21.4g to the reaction bottle, keep the reaction for 5h, the reaction bottle temperature reduces to room temperature, add 0.1mol / L sodium carbonate aqueous solution to the reaction bottle, adjust the system pH=7, stand and separate, the upper solution is washed with saturated sodium chloride solution twice and then with purified water once, the upper solution is transferred to a rotary evaporator with water bath temperature of 85℃, and the low boiling point is removed under reduced pressure to obtain aniline modified fluorine-containing polysiloxane.

[0078] Step three, preparation of polysiloxane reinforcing agent

[0079] Take: aniline modified fluorine-containing polysiloxane 200g, diethyl(chloromethyl) phosphine oxide 80g, toluene 2000mL, base catalyst triethylamine 40g into the reaction bottle stirring, the reaction bottle temperature rises to 78℃, keep the reaction for 8h, the reaction bottle temperature rises to 85℃, and the low boiling point is removed under reduced pressure to obtain polysiloxane reinforcing agent.

[0080] Step four, preparation of polyimide reinforcing body

[0081] Take: polysiloxane reinforcing agent 100g, 4,4'-diamino diphenyl ether 150g, catalyst 4-dimethylaminopyridine 25g and DMSO 500mL into the reaction bottle stirring, the reaction bottle temperature rises to 150℃, stirring until the system dissolves, calculate the addition amount of pyromellitic dianhydride according to 1 / 2 of the molar amount of the amine in the reaction bottle, and mix pyromellitic dianhydride and DMSO uniformly at 1g:1mL to obtain a pyromellitic dianhydride solution, add the pyromellitic dianhydride solution to the reaction bottle, after the addition is completed, keep the reaction for 6h, and then treat, the reaction bottle is cooled to 100℃, and the polyimide reinforcing body is obtained.

[0082] Example 4

[0083] The present embodiment provides a micro-wire production process, comprising the following steps:

[0084] Step I, preparation of fine wire conductor

[0085] After smelting the copper block with a purity of 99.98%, it is subjected to rolling and stretching treatment to obtain a fine wire conductor with a diameter of 0.13mm;

[0086] Step II, preparation of pretreated conductor

[0087] Mixing trimethylamine hydrochloride and deionized water uniformly, adjusting pH=8.5, obtaining buffer solution with concentration of 0.3 mol / L, standby;

[0088] Weighing: 10 g of dopamine hydrochloride and 5 L of buffer solution are added to the reaction bottle and mixed, the temperature of the reaction bottle is raised to 50℃, ultrasonic dispersion, 50 g of fine wire conductor is added to the reaction bottle, ultrasonic deposition for 3 h, the fine wire conductor is taken out of the solution, washed with purified water and dried to obtain the pretreated conductor.

[0089] Step III, preparation of fine wire

[0090] The pretreated conductor is immersed in the polyimide reinforcing body prepared in Example 1 to coat a polyimide coating layer with a thickness of 10 μm on the outside of the pretreated conductor, and a fine wire crude product is prepared;

[0091] The fine wire crude product is transferred to a drying box with a temperature of 260℃, and heat imidization treatment is performed for 30 min to obtain a fine wire.

[0092] Example 5

[0093] The present embodiment provides a production and preparation process of fine wire, comprising the following steps:

[0094] Step I, preparation of fine wire conductor

[0095] After melting the copper block with a purity of 99.98%, the copper block is subjected to rolling and stretching treatment to obtain a fine wire conductor with a diameter of 0.14 mm;

[0096] Step II, preparation of pretreated conductor

[0097] Mixing trimethylamine hydrochloride and deionized water uniformly, adjusting pH=8.5, obtaining buffer solution with concentration of 0.3 mol / L, standby;

[0098] Weighing: 10 g of dopamine hydrochloride and 5 L of buffer solution are added to the reaction bottle and mixed, the temperature of the reaction bottle is raised to 55℃, ultrasonic dispersion, 50 g of fine wire conductor is added to the reaction bottle, ultrasonic deposition for 4 h, the fine wire conductor is taken out of the solution, washed with purified water and dried to obtain the pretreated conductor.

[0099] Step III, preparation of fine wire

[0100] The pretreated conductor is immersed in the polyimide reinforcing body prepared in Example 2 to coat a polyimide coating layer with a thickness of 12 μm on the outside of the pretreated conductor, and a fine wire crude product is prepared;

[0101] The fine wire crude product is transferred to a drying box with a temperature of 270℃, and heat imidization treatment is performed for 25 min to obtain a fine wire.

[0102] Example 6

[0103] The present example provides a process for producing a micro-wire, comprising the following steps:

[0104] Step I, preparing a fine wire conductor

[0105] After smelting a copper block with a purity of 99.98%, the fine wire conductor with a diameter of 0.15mm is obtained through rolling and stretching treatment;

[0106] Step II, preparing a pretreated conductor

[0107] After mixing trimethylamine hydrochloride and deionized water uniformly, adjust the pH to 8.5 to obtain a buffer solution with a concentration of 0.3mol / L, ready for use;

[0108] Weigh: dopamine hydrochloride 10g and buffer solution 5L are added to the reaction bottle and mixed, the temperature of the reaction bottle is raised to 60℃, ultrasonic dispersion, 50g of fine wire conductor is added to the reaction bottle, and ultrasonic deposition is carried out for 5h, then the fine wire conductor is taken out from the solution, washed with purified water and dried to obtain the pretreated conductor.

[0109] Step III, preparing a micro-wire

[0110] The pretreated conductor is immersed in the polyimide reinforcing body prepared in Example 3, and a layer of polyimide coating with a thickness of 13μm is coated on the outside of the pretreated conductor to prepare a micro-wire crude product;

[0111] The micro-wire crude product is transferred to a drying box with a temperature of 280℃, and heat imidization treatment is carried out for 20min to obtain the micro-wire.

[0112] Comparative Example 1

[0113] The difference between this comparative example and Example 6 is that the preparation process of the polyimide reinforcing body used, in step two, 2,4,6,8-tetramethyl-2,4,6,8-tetrakis(3,3,3-trifluoropropyl)cyclotetrasiloxane is replaced by D4 in equimolar amount.

[0114] Comparative Example 2

[0115] The difference between this comparative example and Example 6 is that the preparation process of the polyimide reinforcing body used, step three is cancelled, and the aniline modified fluorine-containing polysiloxane in step two is used to replace the polysiloxane reinforcing agent in step four.

[0116] Comparative Example 3

[0117] The difference between this comparative example and Example 6 is that step II is cancelled, and the fine wire conductor in step I is used to replace the pretreated conductor in step III.

[0118] Performance test:

[0119] Flexibility, breakdown voltage of the fine wire samples prepared in Examples 4-6 and Comparative Examples 1-3 were determined according to the standard GB / T 6109.1-2008 "Enamelled round winding wire Part 1: General requirements";

[0120] Flexibility was the maximum tensile elongation before the enamel layer of the sample cracked (winding elongation) and the elongation at break of the sample surface enamel layer (break elongation) after the sample was wound on a round bar with a diameter of 0.150 mm after different stretching;

[0121] Breakdown voltage was the minimum breakdown voltage of the sample at room temperature;

[0122] The adhesion strength grade of the fine wire samples prepared in Examples 4-6 and Comparative Examples 1-3 was determined according to the standard GB / T 1720-2020 "Paint film circle test";

[0123] The sample was placed in a thermal gravimetric analyzer, the atmosphere was set to air, the temperature range was room temperature to 800℃, and the heating rate was 10℃ / min. The initial decomposition temperature of the sample was determined, and the specific test results are shown in Table 1 below.

[0124] Table 1 - Performance test data table of the sample

[0125]

[0126] Data analysis:

[0127] Comparative analysis of the data in Table 1 above, the winding elongation of the fine wire prepared by the application reaches 25.8%, the break elongation reaches 36.9%, the minimum breakdown voltage reaches 1700V, the adhesion strength grade of the surface enamel layer reaches level 2, and the initial decomposition temperature reaches 555℃. The performance test data is better than that of the comparative example, which shows that the application modifies the fluorine-containing polysiloxane with diethyl phosphorus oxide modified aniline, enhances the polysiloxane reinforcing agent to the polyimide reinforcing body, and then coats the polydopamine modified fine wire conductor. Not only effectively improves the flexibility and high temperature resistance of the fine wire, but also improves the adhesion and minimum breakdown voltage.

[0128] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details and limit the application to the specific embodiments. Obviously, many modifications and changes can be made according to the content of the specification. The embodiments are selected and described in detail in order to better explain the principles and practical application of the application, so that those skilled in the art can well understand and utilize the application. The application is limited by the claims and their entire scope and equivalents.

Claims

1. A process for the production of micro wires, characterized in that, The method comprises the following steps: S1, taking a copper block as a raw material, a fine wire conductor with a diameter of 0.13-0.15 mm is prepared through smelting, rolling and stretching treatment, and a polydopamine layer formed by mixing hydrochloric acid dopamine and a buffer solution is deposited on the surface of the fine wire conductor, that is, the temperature of the reaction system is increased to 50-60 DEG C, ultrasonic dispersion is performed, the fine wire conductor is added to the reaction system, ultrasonic deposition is performed for 3-5 h, and post-treatment is performed to obtain a pretreated conductor; S2, D4, 2, 4, 6, 8-tetramethyl-2, 4, 6, 8-tetra(3, 3, 3-trifluoropropyl) cyclotetrasiloxane, aniline modified diethoxysilane and a catalyst are mixed and stirred, the temperature of the reaction system is increased to 90-100 DEG C, and reaction is performed for 2-3 h, then diallyl tetramethyl disiloxane is added to the reaction system, reaction is performed for 3-5 h, post-treatment is performed to obtain aniline modified fluorine-containing polysiloxane, diethyl(chloromethyl) phosphine oxide, toluene and an alkali catalyst are mixed and stirred, the temperature of the reaction system is increased to 74-78 DEG C, and reaction is performed for 6-8 h, and post-treatment is performed to obtain a polysiloxane reinforcing agent; S3, the polysiloxane reinforcing agent, 4, 4'-diamino diphenyl ether, a catalyst and DMSO are mixed and stirred, the temperature of the reaction system is increased to 130-150 DEG C, stirring is performed until the system is dissolved, a pyromellitic dianhydride solution is added to the reaction system, reaction is performed for 4-6 h, and post-treatment is performed to obtain a polyimide reinforcing body; S4, the polyimide reinforcing body is coated on the outside of the pretreated conductor, a polyimide coating layer with a thickness of 10-13 mu m is coated on the outside of the pretreated conductor, and high-temperature thermal imidization treatment is performed to obtain a fine wire.

2. The process for producing a fine wire according to claim 1, wherein In step S1, the purity of the copper block is 99.98%, the amount ratio of the hydrochloric acid dopamine, the buffer solution and the fine wire conductor is 1 g:500 mL:5 g, and the buffer solution is 0.3 mol / L of trimethylamine hydrochloride aqueous solution with pH=8.

5.

3. The process for producing a fine wire according to claim 1, wherein In step S2, the amount ratio of the aniline modified fluorine-containing polysiloxane, diethyl(chloromethyl) phosphine oxide, toluene and an alkali catalyst is 5 g:2 g:50 mL:1 g, and the alkali catalyst is triethylamine.

4. The process for producing a fine wire according to claim 1, wherein In step S2, the molar ratio of D4, 2, 4, 6, 8-tetramethyl-2, 4, 6, 8-tetra(3, 3, 3-trifluoropropyl) cyclotetrasiloxane, aniline modified diethoxysilane and diallyl tetramethyl disiloxane is 3:1:1:1, the amount ratio of D4 and the catalyst is 5 g:1 mL, and the catalyst is 40-60 wt% sulfuric acid.

5. The process for producing a fine wire according to claim 4, wherein The preparation method of the aniline modified diethoxysilane is as follows: o-phenylenediamine and tetrahydrofuran are mixed and stirred under inert gas protection, the temperature of the reaction system is increased to 40-50 DEG C, 3-isocyanate propyl methyl diethoxysilane solution is added dropwise to the reaction system, reaction is performed for 60-80 min, and post-treatment is performed to obtain aniline modified diethoxysilane.

6. The process for producing a fine wire according to claim 5, wherein The molar ratio of the o-phenylenediamine and 3-isocyanate propyl methyl diethoxysilane is 1:1, the ratio of the o-phenylenediamine and tetrahydrofuran is 1g:4mL, and the 3-isocyanate propyl methyl diethoxysilane solution is composed of 3-isocyanate propyl methyl diethoxysilane and tetrahydrofuran at a ratio of 1g:1mL.

7. The process according to claim 1, wherein In step S3, the ratio of the polysiloxane reinforcing agent, 4,4'-diamino diphenyl ether, catalyst and DMSO is 2g:3g:0.5g:10mL, the catalyst is 4-dimethylaminopyridine, the molar ratio of the pyromellitic dianhydride to the amino group in the reaction system is 2:1, and the pyromellitic dianhydride solution is composed of pyromellitic dianhydride and DMSO at a ratio of 1g:1mL.

8. The process for producing a fine wire according to claim 1, wherein In step S4, the preparation method of the fine wire is: B1, dipping the pretreated conductor into the polyimide reinforcing body to coat a polyimide coating layer with a thickness of 10-13μm outside the pretreated conductor to obtain a fine wire crude product; B2, heat imidization treatment of the fine wire crude product at a temperature of 260-280℃ for 20-30min to obtain the fine wire.

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